co-lor  tem-per-a-ture: noun The temperature at which a black body radiator emits radiation of the same color as a given object.

You may or may not be able to understand the definition of color temperature, but you know it when you see it. The two luminaires in this photo both have compact fluorescent lamps in them. 

Saving energy = saving money = good. 
Mismatched color temperatures = bad.


The one on the left is a cooler color temperature than the one on the right. A cooler color temperature has a higher number, measured in Kelvin, while a warmer color temperature has a lower number. These two are around 3000K and 2700K. When shopping for replacement lamps, make sure to get consistent color temperatures, and decide ahead of time whether you want a warm color like incandescent or a cooler, "whiter" light.

Painting the walls a dark color, or not painting the walls at all. A key factor in the brightness of any space is the reflectances of the surfaces. The more reflective your walls, ceiling, floor, and furnishings, the less it will cost to make the room feel bright. A can of white paint is one of the most inexpensive lighting accessories you can buy.

Closing shades or draperies to keep out daylight. (Or letting the daylight in but leaving the lights on anyway.) Daylight is free, has all of the characteristics people crave in lighting - good color rendering, changing throughout the day to improve circadian rhythms, and did I mention free? Adjust the blinds to direct glare toward the ceiling, but keep the light switch off when the sun is shining.

Not using dimmers. At certain times of day or on certain days of the year people need or want more light. At other times, less is better. Dimmers save energy and increase lighting satisfaction by giving occupants control of their spaces. They're easy to install. Do it. You'll be glad you did.

Forgetting to take advantage of warranties. Sure, we've all had bad experiences with either an LED or CFL lamp. But do your research to find a high quality product from a reputable manufacturer that meets your lighting specifications. Then hold them to their warranty. If something goes wrong, don't go elsewhere. Go back to the manufacturer and get them to fulfill their warranty. That will help them improve the products in the long run, too.

Avoiding new technology. New technology does require you to understand more about lighting and the visible spectrum. You have to watch for the right color temperature and good color rendering. Lighting quality issues aren't simple. But if you choose carefully, the energy savings will be worth the extra front-end effort.

Which lighting mistakes are you making? Which is most surprising to you?

I recently had the opportunity to do a mock-up at home. I was comparing the new Soraa MR-16 LED lamp with my existing halogen MR-16 lamps. Soraa was one of my favorite new products at last year's LightFair, and they continue to impress me. You can easily see how clean the beam is by comparing the two photos above. Less evident from the photo is the fact that the Soraa LED renders the wall more like daylight does. These lamps also have a little backlight, so while admittedly not as nice as with the halogen lamps, the glass fixtures where they are installed do glow a little.

I have been reluctant to hop on the LED bandwagon, but my recent experiences have been good ones. We are not all the way there yet, but I think we are getting warmer! The important thing is for lighting manufacturers (and legislators) to focus on lighting quality and not just lighting quantity.

Over the weekend my family and I had the pleasure of helping sort lights for the Holiday Light Recycling Drive with St. Louis Green. I love volunteering alongside my family, and the fact that proceeds from this event supported a great cause - Operation Food Search -  made it even better.
The goal is for 128,000 pounds of waste to be diverted from landfills. The lesson for me as I sorted? Be careful what you buy!
Reduce, Reuse, Recycle? We do a lot of recycling these days. Maybe we should take a closer look at the first word in that phrase...reduce.
It is so easy to get caught up in consumerism, but what if we remember to refrain from making unnecessary purchases? Isn't that the most "green" choice of all? It may not stimulate the economy like "going shopping" but reduction makes good economic sense on a personal level.

One of our sorting tasks this weekend was to separate cardboard from lights, and in many cases there were brand new boxes of lights that had never been used. I kept wondering what scenario would lead to someone depositing brand new boxes of lights into the red recycling bins. But then again, I have some "extra" unused lights stored away in a box in the basement myself. Do you have boxes of unopened holiday lights at home? What future purchases can we avoid if only we remember step #1? Reduce.

I was recently in one of those big box home stores helping my parents shop for things for the new house they are building. We looked at lights and ceiling fans. We checked out some electrical devices, outlets, and switches. We looked at carbon monoxide and smoke detectors - hard wired or battery powered? Dual technology or separate? We checked out some appliances. We walked all the way around the store looking for a public restroom... My point is that we were there for a while - 30 minutes or maybe an hour - when I noticed that someone in the lamp (light bulb) aisle was standing in the same place staring at the same lamps when arrived AND when we left.

It used to be so easy. The only question you had to answer when replacing a light bulb (lamp) was, "How many Watts?" But that was then. I'm here to save you a few minutes in the lamp aisle at the home store. Before your next trip, be armed with the answers to the following five questions:

1. How Bright?
Today we have to think in Lumens instead of Watts. An old 100 watt lamp produced about 1600 lumens. A 60 watt standard incandescent lamp is about 800 lumens, and 40 watt incandescent = about 450 lumens. Before you shop, know how bright you need the light to be - in lumens.

2. What Color?
Not all "white" light is the same color. For more on that topic, check out the pictures in this previous post. The point is that most of today's sources are available in different color temperatures. To most closely resemble incandescent light, select a warm hue, between 2500 and 2800 Kelvin.

3. Where Used?
This question really embodies lots of other questions. Is it in an enclosed fixture? Indoors or outside? In a transient space like a closet? Somewhere extremely hot or cold? Is it used to accent a piece of art, or does it need to be fairly shadow-free? Certain CFLs don't do well in winter temperatures, LEDs prefer the cold. Most LEDs aren't designed for fully enclosed fixtures. Many CFLs aren't either. CFLs generally take a little time to get fully bright, so they might not be the best choice for closets. LEDs tend to be very directional and better for accent lighting, but can be diffused for general lighting. CFLs are great for general shadowless illumination but are never very directional. Know where the new lamp will be used.

4. How Controlled?
Is the lamp you are replacing on a switch or a dimmer? If it is controlled with a dimmer, replacement options are more limited, and you should check dimmer compatibility before you purchase a replacement.

5. How Much Money?
Consider both initial cost and ongoing costs. To spend the least money today, buy an incandescent or halogen replacement lamp. In the long run, this choice will cost the most in energy and replacement lamps, even though the initial outlay is the smallest for this category. The middle of the road option is fluorescent. It will cost a little more today, but will last a little longer and save a little more energy than the traditional sources. Top of the line is LED. These still cost the most, but will provide the most light per watt and will last the longest...provided you buy a quality product and use it in an appropriate application.

If you head to your local light bulb store with the answers to these questions in mind, you should save yourself a few minutes. Maybe you'll even have enough time to browse the clearance aisle and get one of those inflatable snow globes at 75% off!

I’m Dreaming of an LED Christmas...

As a lighting designer, one of my favorite things about the holidays is the lighting. I love the soft flicker of candlelight, the twinkling tree lights, and a warm fire in the fireplace. It’s the time of year when most everyone dons their Santa/lighting designer cap and changes the lighting in their home for a month. Whether you string icicle lights around the roofline of your entire house or just wrap a strand of lights around a tree or wreath, you are being faced with this question: to LED or not to LED?

Five things to consider:

1.     Initial Cost - These lights still cost more than standard incandescent holiday lights. However, from the looks of today’s store shelves, LED will be your only future option. You already have to search a little to find the standard incandescent lights.

2.     Energy - Over their lifetime, these lights will pay you back what you spent and more on your electric bill. Here’s what the Department of Energy has to say about it. (Scroll to the bottom for the Holiday Lights section.) This is all theoretical, of course. Reliability is improving all the time, but my personal experience with LED holiday lights has been about a 30% early failure rate. Perhaps I’m just unlucky. The lights are guaranteed, but time is precious – especially during this season.

3.     Color - As with all of the new technologies there are choices to be made about color. At least with Christmas lights we are used to thinking about color! Look at the samples before you make your selection. Some white lights are more blue in color while others look more yellow. Which look do you want? The icy wintry blue look or the warm glow of the yellowish lights?

4.     Environment - To be environmentally responsible, don’t use any lights at all. To be both festive and environmentally responsible, just make sure you don’t add more lights since you’re saving energy with LEDs. Better yet, consider the solar LED products that are hitting the shelves today. You will still contribute to sky glow, but you won’t be consuming electricity with your light display.

5.     Recycle!   Remember – when you do toss out all of those old strands of lights - recycle them! In the St. Louis area, we are partnering with St. Louis Green to recycle 128,000 pounds of lights this year. That’s literally tons of waste that will be diverted from landfills. And hopefully every one of those strands will be replaced with a lower wattage, longer lasting option.

Tell us about your experience. Do your LED holiday lights work well? Have you noticed a difference in your electric bill? Have you had any luck with solar LEDs?

...May your days be merry... and bright!

As promised, here are my IES Conference notes! If you missed the Conference in Minneapolis two weeks ago, you missed a good one. If you were there, feel free to add comments about the seminars and paper sessions you attended.

For me, the Conference began on Saturday when we hosted 40 students and emerging lighting professionals with a full day of topics designed just for them. We toured an award-winning U of M campus building, had portfolio reviews, and gave everyone time to "speed network" with all kinds of lighting professionals. Our opening keynote speaker is an emerging professional herself - Maja Petric shared her inspirational use of light in her art. Her most architectural work used LED light to pour through cracks in a tunnel ceiling to illuminate the inside of the tunnel. The color temperature and intensity of the light changes throughout the day to mirror the current outdoor light conditions. See that project and more of her beautiful work here. It was her work that inspired me to post this.

When the Conference-proper kicked off on Sunday, we danced the night away to the delightful sounds of Stefan Graf's lighting industry band, Black Body Locusts. Special thank you's go to Naomi Miller for writing hilarious lighting lyrics for the band to sing and to Lance Bennett / Cooper Lighting for sponsoring the band!

The next day the dean of the University of Minnesota School of Design, Thomas Fisher, challenged us to not just problem solve, but problem seek. Design thinking is valuable beyond the making of things. He even wondered if universities should be restructured - not around disciplines, but around world challenges. In this format, the iterative process of abductive reasoning could be put to work: seeing connections between things that are seemingly different. Who knows the discoveries that would follow? Are we defining our industry correctly? Is it lighting? Or perhaps we are in the human productivity business? This led the way for professor Blaine Brownell to describe the lighting immersion project created by his architectural students. They gather all kinds of materials and, working in teams, build a light of some kind. Some of the projects make statements, some are portable, some explore the idea of light as an object that occupies space rather than illuminating it. All of these projects are unexpected and creative. For more from Blaine Brownell, start here then read one of his books.

Next I attended the "LIGHT+ SENIORS Symposium Summary and Review." All I can say is - wow - am I ever sorry I missed the symposium! The Summary and Review was so full of information that I'll revisit this one later in a blog post all its own.

If I thought I was mentally saturated before the "Smart Lighting - Beyond Ordinary" session, I certainly was afterward. This future-casting session covered everything from the invention of LED to synthetic LED skylights (light + video) to the use of blue light "patches" for pain therapy (light + medicine) and of course, the new hue LED from Philips sold in your local Apple store (light + apps.) Light carries information. Imagine one day using our light sources instead of broadband... It's all about the fusion of lighting and other disciplines. Are you catching the theme? The whole conference theme of synapses and connections was repeated through many sessions where interdisciplinary interaction was lauded and encouraged.

Monday night's entertainment was a private screening of the documentary The City Dark. It was fun seeing some of our very own IES Conference attendees (Howard Brandston) on the big screen. The movie itself pits lighting on earth against the night sky's fading natural lights and challenges us to balance the two. Heavy.

The next morning's keynote speaker was Mark Major who picked up the dark sky theme with excerpts from a National Geographic article on Light Pollution. What should we be more afraid of? The dark? Or what we are doing to the night? The work of Speirs + Major is always breathtaking, and hearing this one presentation was worth every penny I spent on the entire conference.

In the next session, I was privileged to introduce my fellow KU alumnus, Zachary Suchara, who spoke on human factors in lighting. When was the last time you considered your humanity as it relates to lighting? Humans are phototropic. Exactly how we experience light varies based on where we live on the planet. Zach had many other fascinating points including this one: In the past 20 years, there have been more new lamp types developed than in all the other years of human history put together. He closed the session with a great case study in which the developers exploited the human factor by turning the building systems into a game. Tenants in the building actually compete with each other to see who can use the least energy. It reminded me a little of watching the gauges on our Toyota Prius to see how many miles per gallon we can get per trip.

The Conference included many more papers, some political pundits, the always-popular Progress Committee presentation, a wonderful Illumination Awards dinner, other Society Awards, and lots of networking. For me, it was one of the best IES Conferences ever. How about for you?

'Tis the Season to Recycle!  Reduce waste and spread cheer this holiday season by donating your broken or unwanted holiday lights to St. Louis Green's 2012 Holiday Light Recycling Drive!  This year, St. Louis Green hopes to divert over 128,000 pounds of lights from entering our landfills.  And not only does the Drive help protect the environment, but it also helps feed the hungry. A portion of proceeds from the drive is donated to Operation Food Search, helping those less fortunate to have a happier holiday season.  Learn more at http://www.stlouisgreen.com/Holiday-Light-Recycling-Drive.

This year's St. Louis IES Illumination Awards event was again declared the "best" by many attendees! We had a beautiful time, enjoyed a Planetarium Star show, then were entertained by our own stars' interviews on a mock "Ronahue" Show about their lighting design projects. Three Illumination Award projects were introduced via movie previews. See the movie previews here:

Watch the St. Louis IES website for more details about this event and for information about future events. 

Color is so much stranger than it seems at first glance. When we were children learning red, green, yellow, orange, blue...it seemed so straightforward. So easy to get the right answer. When did you realize that it was all a sham? An illusion? For me it happened in high school when I always wore socks to match my shirt (yea 80's!) I bought a pair of royal blue socks - perfect - until I got them home under the incandescent light. They were purple. What? Okay, then, fine. I'll wear them with my purple shirt - until - I got to school and they were blue again. How mortifying. What had happened?

In the previous post we looked at the color temperature, or color of the light. That actually has little to do with color rendering, which is the color of the objects under the light. See the difference? Either a warm source like incandescent or a cool source like daylight can render the color of objects nearly perfectly (my socks were blue under both.) It has to do with how much of the pigment is reflected back to your eye by the light source.

The three pictures above subtly illustrate differences in color rendering (or color accuracy) on the apple. The apple is the same, but it appears more pink, orange, or deep red under different lights. In the picture on the right the yellows in the apple are easier to see; In the middle picture, the dark lowlights are well defined; The one on the left seems smooth in color - neither the lowlights nor the yellows are obvious. It is important to know not only whether a source is warm or cool (color temperature) but also how it renders the objects under its light (color rendering.)

The new Lighting Facts Label (at left) required on light bulbs (lamps) sold in the US lists the color of the light, but not its color accuracy. Another new label (below) uses both. As a consumer of today's complex lighting sources, you need to know both. The color accuracy scale goes to 100. In most cases, choose the highest number you can afford. Something in the 80s for fluorescent and close to 90 for LED. If you have the opportunity to try multiple sources to see how they look in your final application, that is even better. Check color accuracy to avoid disappointment and purple...no, blue...no, purple socks - or worse!